Image Map Image Map

Search:

Type: Posts; User: durgadas311

Page 1 of 20 1 2 3 4

Search: Search took 0.02 seconds.

  1. Swapping out the resident part of CP/M is really...

    Swapping out the resident part of CP/M is really not always possible. If your systems uses interrupts - especially for the system clock - you can't take an interrupt while the user has banked-out the...
  2. A common misconception, but the banked memory...

    A common misconception, but the banked memory size does NOT determine the TPA size. It is the resident OS size that determines the maximum banked size, and *IS* the TPA. Since RESBDOS is usually...
  3. CP/M 3 was intended to be a single-user...

    CP/M 3 was intended to be a single-user single-tasking OS. So there is only one TPA. Note that the TPA is not limited by the common memory boundary, but by the size of the resident BIOS/BDOS. So even...
  4. Alan, short answer is probably that you need to...

    Alan, short answer is probably that you need to ignore the BC field. But even then, it is possible for text files to have different data after the first Ctrl-Z, as I don't think copy/edit programs...
  5. Most programs didn't need to. But it was nice to...

    Most programs didn't need to. But it was nice to have in some situations.
  6. read and write still work on 128-byte records....

    read and write still work on 128-byte records. Nothing about those operations changes. Checking (or setting) the byte count is a voluntary operation that the programmer may choose to use. The default...
  7. CP/M 3 allows you to set the BC (byte count),...

    CP/M 3 allows you to set the BC (byte count), after writing the last (full) record. In other words, you write the last record and specify the actual EOF somewhere within that last record. Function 30...
  8. CP/M 3 use of the BC field is supposed to be...

    CP/M 3 use of the BC field is supposed to be backward compatible - i.e. CP/M 2.2 should not alter it (I think). They endeavored to make all of the CP/M 3 extensions to the filesystem "benign" when a...
  9. Replies
    8
    Views
    597

    Right, PIP's way is definitely "brute force". It...

    Right, PIP's way is definitely "brute force". It did save TPA for buffering the files being copied, though. In your case you probably don't need to buffer the entire file in memory. Some directories...
  10. Replies
    8
    Views
    597

    The 2.2 BDOS does remember the FCB passed into...

    The 2.2 BDOS does remember the FCB passed into function 17, and re-uses that for function 18. However, it also depends on more context than that. It must have the contents of the DMA buffer that was...
  11. No, that code could mean EOF as well. There is an...

    No, that code could mean EOF as well. There is an error code 04 "Seek to unwritten extent" which might differentiate, but unclear what you get when reading a block that has not been allocated within...
  12. Random Access was added to relieve the programmer...

    Random Access was added to relieve the programmer of implementing their own extent-manipulation code. Previously, database programs - for example - had to implement and debug fairly "rough" code to...
  13. Replies
    12
    Views
    775

    Sure, well help is available. What sorts of...

    Sure, well help is available. What sorts of expansion interfaces do you have? Any schematics to look at?

    BTW, the upcoming "GIDE" interface (compact flash adapter or IDE harddisk) on Norberto's...
  14. Replies
    12
    Views
    775

    FYI, no floppies are required with the Heathkit...

    FYI, no floppies are required with the Heathkit hardware, although I doubt that is what you are looking for. I mention it because the H8 system bus is fairly well defined and has a long track record....
  15. Replies
    12
    Views
    775

    I have a history with Heathkit/Zenith computers...

    I have a history with Heathkit/Zenith computers and so have been a member of the sebhc google group. But one site of particular interest is http://koyado.com/Heathkit/. Norberto has been...
  16. Replies
    10
    Views
    826

    I seem to recall seeing some attempts to do that,...

    I seem to recall seeing some attempts to do that, but can't think of a specific example.

    If you have a corrupted filesystem and are trying to repair it, one possibility is to image the filesystem...
  17. Ah, that makes your situation a little clearer....

    Ah, that makes your situation a little clearer. You are emulating the Epson BIOS.
  18. The BDOS (SELDSK function) error codes that Chuck...

    The BDOS (SELDSK function) error codes that Chuck refers to are quite different from the BIOS error codes, which I believe you were asking about. BIOS return codes may be extended, but those only...
  19. SELDSK is called by the BDOS (the most frequent...

    SELDSK is called by the BDOS (the most frequent user of the BIOS) before it performs a READ/WRITE. It is unlikely, possibly never the case, that the BDOS will not follow a SELDSK by SETTRK, SETSEC,...
  20. Typically, no media in drive is reported during...

    Typically, no media in drive is reported during SELDSK, as a "SELECT" error. If the media somehow got removed between SELDSK and READ/WRITE, it would get reported as a bad sector.
  21. Replies
    10
    Views
    853

    I did some more investigation. As a simple case,...

    I did some more investigation. As a simple case, "[LF000,DEC00]" seems to do the right thing. It appears to discard the dseg region and ORG dseg at EC00 (and ORG cseg at F000), and the first byte of...
  22. Replies
    10
    Views
    853

    Looking at CPNIOS.ASM, I see that it copies the...

    Looking at CPNIOS.ASM, I see that it copies the network config table into RAM, and has a "well behaved" dseg with no initialized data. CPNDOS.REL definitely does not have that, and I don't think that...
  23. Replies
    10
    Views
    853

    I did some experimentation. I think the confusion...

    I did some experimentation. I think the confusion is about what "load address" means. That specifies where the lowest address in the image will be located in memory. I get a more-resonable image when...
  24. Replies
    10
    Views
    853

    One thing is that the link command is producing a...

    One thing is that the link command is producing a COM file - is that what you intended? It's been a long time since I've used DRI tools to generate a ROM image, but it seems to me you need more...
  25. Replies
    10
    Views
    853

    The other thing to check is why the...

    The other thing to check is why the READ_SEQUENTIAL of CCP.SPR stops after 4 records. Can you examine the response message(s)? An error from the server during loading of CCP is likely to send you...
Results 1 to 25 of 500
Page 1 of 20 1 2 3 4